A mass spectrometric depletion measurement has been performed for the $NO_{2}$ molecule in its bound region as well as above its gas phase dissociation threshold. In the bound region ($17700 - 18300 cm^{-1}$) that is known to be vibronically chaotic transitions are broadened and blue-shifted relative to their gas-phase counterparts. The spectrum is fitted relatively well by setting all shifts and width equal to $7 cm^{-1}$. Modest dispersion of these values are consistent with quantum chaos in $NO_{2}$. Relaxation is dominated by interaction of $NO_{2}$ with its non-superfluid helium nearest $neighbors.^{a}$ In the region above the gas-phase dissociation threshold ($25125 - 30000 cm^{-1}$) the mass depletion spectrum reveals no fine structure. The fast relaxation due to the interaction with the superfluid helium environment prevents photodecomposition of the $NO_{2}$ molecule over the entire range we explored.